[DoDEA Science]


DRAFT

Tides

Astronomy


Grade Level 10 - 12
Standards Inquiry Skills
    Students will design and conduct scientific investigations
  Astronomy Content
    Students will describe physical characteristics of the moon and quantitatively evaluate the moon's effect on the Earth
  Science and Technology
    Students will demonstrate abilities in technological design
Objectives
  1. Use orbital and physical characteristics of the moon( i.e.. mass, diameter, distance from Earth) to explain the positions of the sun, moon, earth system.
  2. Explain how the moon affects the Earth's tides and the impact of these tides on the Earth's economy.
  3. Apply Newton's law of gravitation, F= GMm/d2 to prove the strength of the force of gravity on the tides. Understand the force differential for the sun and the moon.
  4. Use Excel to solve a mathematical problem.
  5. Interpret the graph of force differential for the sun and the moon.
  6. Apply knowledge about tides and gravity to the other planets' moons. 
Materials and Activities
Materials Microsoft Excel
Engage Students will be asked to answer the following questions:
  1. What causes the tides?
  2. Which is greater the gravitational force between Earth and Sun or Earth and Moon?
Students will be given the following formula to calculate the gravitational forces:
F e-s= G Me Ms = ( de-s)2
Fe-m= G Me Mm = ( de-m)2
Students will use the textbook, Appendix 2A to look for the basic constants, for the above formulas. The students will use a spreadsheet in Excel to calculate the forces. ( The gravitational force of the Sun is greater)
Explore Students will now calculate the differential force that is applied to the earth by the moon and the sun. To do this they will need the following formulas:
Force of Earth-Sun near side: F = G*MeMs (de-s - re)2
Force of Earth-Sun far side: F= G*Me*Ms (de-s + re)2
For the force of the Earth-Moon, substitute Mm for Ms and de-m for de-s
Students will need to use Excel to fill in the data and formulas.
Explain Students will produce a graph to show force differential to show the moon and the sun. Students will be able to explain their findings and how the differential forces cause tides.
Elaborate Students using the Internet and other sources will do an oral report on tides as sources of energy, how tides effect our Earth's economy in regards to erosion, fishing, and recreation. 
Evaluate Students will be given an application problem related to the moon's of Jupiter. Tidal forces and the effects on multiple moons will be the focus of this application problem.
Homework Students will work on the oral reports of the effects of tides on the Earth and mankind as long-term homework.

Teacher notes/reminders: The force of the sun on the earth is much greater than that of the moon. However, it is the force differential that causes the moon to be the main influence.


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Updated 9/00
Last Reviewed 10/2001

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